External Fixators Flashcards
What two components to external fixartors are there?
beam and pins
What are the orthopaedic uses of external fixators?
limb lengthening limb shortening joint fusion correction of angular/rotaitonal deformity bone segment transportation
What are the uses of post-trauma external fixators?
temporary
definitive
What is the use of tempera external fixation>
maintains stability of the bones while access is safely gained to the soft tissues for dressings or further surgery - once soft tissues have healed they can be changed to another treatment method
What is definitive external fixation?
use of external fixators through soft tissue healing and right through to bone healing
what two principles are in play when configurating external fixators
the bone/frame construct must be stable not rigid
pin placement must not tether soft tissues or restrict wound access
What are unilateral frames?
configurations where they pass through one side of the limb and enter the proximal cortex and end by just passing through the opposite cortex
If pins are not stable enough in a unilateral frame - what design can be employed to increase this?
A or V frame - situating pins at right angles to each other
What determines stability external fixators?
configuration of the frame degree of contact between the bone ends extent of soft tissue injury quality fo the bone/pin interface degree of clamp tightness total number of pins used
What is dynamisation?
modification of the construct which permits the transition of forces across a fracture without allowing distraction of the fragments
When is dynamisation used?
when the soft tissues are well on the way to healing
the simple unilateral frame is to be used for definitive fracture control
What are the advantages of external fixation?
assembled and fitted to the body fairly quickly which is useful in emergency
can be adjusted later if positions are unsatisfactory
the beam can be removed to take very clear x-rays or feel fracture stability
versatile on different sites without changing the basic model so keep stocks low
excellent soft tissue access
What are the disadvantages of external fixation?
infection at the bone-pin interface
pin loosening especially with weight bearing
soft tissue tethering by pins between skin and bone - sometimes inevitable
Describe some fixator complications
module components may work loose
may not be appropriate construction and fracture stability may be lost
What should be done with a loose infected pin?
should be re-sited - if dead bone areas are seen they should be drilled out and cleaned
